A/C Clutch Circuit Low Voltage (Ground Short)
The B1345 code indicates a short-to-ground condition in the A/C clutch input circuit. When the PCM commands the A/C clutch relay to open (de-energize), it still detects a ground signal on the input circuit, meaning the voltage is below the expected threshold. This suggests an unintended direct connection to ground, preventing the clutch from disengaging properly.
1. Commonly Affected Makes
2. Most Common Causes
- A/C clutch relay stuck closed
- Short to ground in the A/C clutch input circuit wiring
- Internal short in the A/C clutch coil
- Failed PCM (internal short)
3. Symptoms You Will Notice
- A/C compressor runs continuously even when A/C is off
- A/C system may not cool properly
- Possible battery drain or blown fuse
4. Step-by-Step Diagnosis
Check for blown A/C clutch fuse and replace if necessary.
Inspect A/C clutch relay for sticking; test relay operation.
Measure resistance of A/C clutch coil; compare to specs.
Check wiring harness for chafing or damage causing short to ground.
If all else passes, test PCM output circuit for internal short.
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, but the A/C compressor may run continuously, which can lead to compressor damage or battery drain. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
Typically $150–$400, depending on the cause. A relay or wiring repair is cheaper; PCM replacement is more expensive.